1.7. Using Spare CPU Cycles

Some Linux applications use idle time in computers to cure diseases,
study global warming, or any other scientific research.
They run as a
low-priority process (nice 20), so you can work without noticing
that it's doing its task. Another use is for people who use P2P
software and leave the PC turned on for long hours unattended, all
that time the PC can be using the electricity it is consuming for
a practical purpose: